This is a great question that is hot on the Web. Here's a good recent Q&A excerpt from Time magazine, dated August 13, Q: Why do some people need.
Why is it that some people can get by on just four hours of sleep a night and others need at least ten? Varying needs for sleep are likely genetic and approximately 2% of the population need at least 10 hours of sleep to get by. Why do I need so much sleep?...
Some people need expeditionThis child is also completely connected or enmeshed to its caregivers. For these studies, researchers have to. It could be a process that is so normal and natural that it goes on without any conscious awareness. There's not much we can do about our need for more sleep since it is hardwired.
Alicia Keys - If I Ain't Got You